An Iranian man held for four-and-a-half years by Somali pirates has been released and is on his way home.

Iran Press/Africa: A humanitarian group working to free people taken hostage by Somali pirates in recent years said in a statement Saturday that Mohammad Sharif Panahandeh had become increasingly ill and couldn't have survived much longer.

The organization says he was one of four remaining hostages held in Somalia, New York Times reported.

The men were in an Iranian fishing vessel which was captured in March 2015.

"Panahandeh will return to Iran in the coming days after medical tests," the statement said adding that the three remaining hostages are being held in "appalling conditions".

Piracy off Somalia has dropped in recent years after a multinational patrolling effort. 101/207